Reducing computational requirements when processing in a swizzled representation, an image portion having a dimension not equaling powers of 2. In an embodiment, the pixels of a source image are stored in a memory in a sequence determined by a swizzled representation. Data indicating boundaries of the image portion of interest are received. A counter is then set to indicate a first position in the swizzled sequence, and a check is performed of whether a position indicated by the counter corresponds to a pixel within the boundaries of the image portion. The counter is incremented by a number of subsequent pixels in the swizzled representation which are not part of the image portion if the position does not correspond to within the boundaries of the image portion. The pixel indicated by the counter is then processed.